Complex Impedance Spectroscopy Studies of BaTiO3 Ceramic with 10% BaFe12O19 Substitution

Barium titanate with 10% barium ferrite substitution (BaTiO3-BaFe12O19) has been synthesized by the solid state reaction route. Formation of the BaFe12O19 phase confirmed its existence in the composite. Impedance spectroscopy study of the composite sample was performed at different temperatures of 25, 40, 80, 120 and 160 °C. BaFe12O19 substituted sample shows a single semicircle at lower temperature and two overlapped arcs at 120 and 160 °C due to grain and grain boundary. The impedance plots were fitted based on a parallel R-CPE circuit. The grain boundary resistance behaves like the positive temperature coefficient of resistivity (PTCR) for donor-doped BaTiO3 semiconductor. The highest capacitance is contributed by the grain boundary at 80 °C.